I think its a mixture of disbelief that his godfather of all people would hurt him, and then to top it off the man who he thought would like to kill him on a daily basis, saves him once again. He's def covering up for the fact that he's not ok, but he doesnt want Ron to get all serious and protective again, even if it was a nice change. As of right now, he doesnt know that Snape knows a part of his life that he'd rather stay hidden Hope that helps.

Yea, I dont think they do, maybe they were hoping they would get back before he does? lol